We definitely didn't see that coming!

Ben Foster and Laura Prepon made their red-carpet debut last night at The Girl On The Train premiere -- but that's not all they did! The twosome couple didn't just tell the world they were a couple, Laura also debuted a diamond sparkler on her ring finger. That's right -- the two couple are engaged, confirms People. If you're gonna go big -- go bold!

If you're scratching your head, remembering that Foster was engaged to Robin Wright in 2015 -- you'd be correct! We haven't heard any news that the Orange is the New Black star was dating the Six Feet Under star, so the happy news comes as quite a shock -- but they've apparently Prepon has known him since she was 18 through pal Danny Masterson.

Prepon is the second OINTB star to show off an engagement ring this week. Her co-star on the show, Samira Wiley, got engaged to the show's writer Lauren Morelli, who split from her husband in 2014 after realizing she was gay while writing the Netflix comedy.

Yes.

A photo posted by Samira Wiley (@whododatlikedat) on